import java.net.SocketTimeoutException;
import java.util.Scanner;

public class test2 {
    static void main() {
        Scanner sc = new Scanner(System.in);
        System.out.println("请输入一个数字表示需要的服务");
        int s = sc.nextInt();
    switch(s) {
        case 1-> System.out.println("机票查询");
        case 2-> System.out.println("机票预订");
        case 3-> System.out.println("机票改签");
        case 4-> System.out.println("退出服务");
        default -> System.out.println("退出服务");
    }


    }
}
